Orchard heater



imma@ i6, 1942.

W. A. LEA ETAL.

ORCHARD HEATER Filed Nov. 26, 1937 2 Sheets-Sheet l For Maf/)w1 June 16,1942. w. A. LEA ETAL 2,285,366

ORCHARD HEATER Filed Nov. 26, 1937 2 Sheets-Sheet 2 l Patented June 16,1942 's UNITED STATES PATENT ori-ICE oRCHARD HEATER Walter A. Lea, LosAngeles, and Earl Vincent Ehrhardt, Altadena, Calif.

Application November 26, 1937, Serial No. 176,614

3 Claims.

This invention relates to air heaters andparticularly to heaters adaptedfor use in batteries of units for heating extended areas at a pluralityof points of heat generation. In the description and drawings, orchardheating has been selected as an illustration of a type of installationof heaters of our invention, but We do not wish our invention to beconsidered as limited to this adaptation, since it is also capable ofemployment to heat shop rooms, buildings, and'other extensive volumes ofair.

It is one of our objects to provide a heater which shall completely andefficiently burn a gaseous fuel supplied to it without the production ofsmoke, soot, or other products of incomplete combustion.

It is another object to provide a heater which shall be automaticallyignited by the flow of fuel to the heater, or by the pressure of thefuel in the supply conductor.

It is another object to provide a heater which shall be adapted toreceive a fuel of the type which is liquid within the range ofatmospheric temperatures above freezing at pressures above atmosphericnormal, but which is gaseous at temperatures above freezing at normalatmospheric pressurel and shall be further adapted by lowering itspressure to convert a liquid fuel of this type into a gas and then burnit.

It is another object of our invention to provide a heater which shall beconstructed to mix and heat air with the heated products of combustionand thereby increase the quantity and velocity and lower the temperatureof the resulting mixture of gases discharged from the heater.

It is still another object of our invention to provide a heater havingboth a pilot burner and main burner and consuming fuel supplied underpressure in which either the pilot or the main burner shall operateaccording to the degree of pressure in the supply conductor.

It is still another object of our invention to provide a heater whichshall discharge its heated products in a desired horizontal directionand more particularly in a focused horizontal stream, to more graduallyand uniformly warm the ground air, than is4 otherwise possible, to theend that the layer of warm air at higher levels which is above thesafety temperature may not be penetrated by localized currents ofvertically moving columns of hot air. This feature, by which we are ableto propel the heated products in any desired horizontal direction, makesit possible to Y oppose, halt. and turn back horizontally movingcurrents of cold air that may be moving toward or .into the orchard orother area which it is desired to warm.

It is a further object of our invention to provide a heater which shallbe so constructed as to secure its heating effect principally fromconvection, and which shall havea minimum of'radiation to the end thatthe ground and surrounding objects may not be unduly heated withdestructive effect. l

Our invention, also, has as -one of its objects the provision of aheater which shall be adjustable in rate of output of thermal units froma relatively very small quantity to a quantity of heat units much aboveprior practice in orchard heating, to the end that fewer heater unitsmay be required in a given area, and at the same time no disadvantagesflow from the corresponding greater concentration of heat emitted fromeach u nit, such as scorching the ground or foliage or piercing theceiling f warm upper air stratum.

It is a further object of our invention to make provision for the use ofour heaters in batteries which shall be subject to a unitary remotecontrol of the ignition, for the selection of either pilot or mainburner, and of the rate of production of thermal units of the individualheaters.

It is a further object of our invention to provide a heater which eithersingly or in batteries may be supplied with a fuel in liquid form inconductors of small size and cost, which fuel shall be converted togaseous form at the heater units. To accomplish this advantageousresult, we prefer to employ as fuels butane, propane, pentane, hexane,or other hydrocarbon of this type, which are liquid at all ordinaryatmospheric temperatures above `freezing in combination withsuperatmospheric pressures ranging upward from about ten pounds persquare inch, depending upon the temperature and the particular type offuel,' but which fuels at the same temperatures are gaseous at normalatmospheric pressure. Wel accordingly-Store the fuel in tanks underpressure, and pipe it under pressure and in liquid l:

form to the heater units, where the pressure is released and the fuel isgasiiled and burned.

It is a further object of our invention to provide means for maintainingthe pressure in the supply system suiliciently high to ensure the fuelbeing in liquid form until it reaches the heater units, and also toensure a constant rate-of supply to the heaters, with a resultantconstant rate of liberation of thermal units.

Still other objects and advantages of our inthe burner end of the heatertaken along the line 5-5 of Fig. 4, the pilot assembly being shown inside elevation in front of the section plane.

Fig. 6 is a vertical sectional view of the pilot assembly taken alongthe line 5-6 of Fig. 5.

A horizontally disposed cylindrical heater flue II receives the jet ofburning gas at its one end I3, and conducts and directs itlongitudinally within its interior chamber I2, the heated products ofcombustion being discharged horizontally from the other and open end I4of the ilue II. As the Jet of flame travels through the flue, air isdrawn in through louvered apertures I5.. These apertures I5 are designedto supply an excess of air, this excess is mixed with and heated by thehot gases of combustion, and both increases the volume and velocity andcorrespondingly lowers the temperature of the resulting gaseousdischarge from. the ue. The cold air entering through the apertures I5also lowers the temperature of the ilue walls and reducesradiationtherefrom. f;

The imector action which tends to draw air into the stack is greatest'at the burner end I3 of the stack and least at the discharge end I4.`Accordingly the apertures .I5 maybe of variable size,increasingprogressively from the burner end I3 to the'discharge end I4, being soformed that the planes of the louvered apertures are progressivelychanged in angular relationship to the plane tangential to the adjacentAportion of the flue wall, the planes of the bounding edges of thevapertures at the burner end lying fiat in the flue wall, and the planesof the bounding edges of the apertures at the discharge end being tiltedat a substantial angle to the longitudinal lines of 'the ue wall. Thisdesign of the louvered apertures provides for an intake of air into theflue in substantially equal amounts through the several apertures,irrespective of their position longitudinally of the flue, since theapertures of greater diameter and greater angular set at the is movableupon the ground l1. The vertical cylindrical end wall 22 of the flue IIis formed with intake openings 23 to admit air to the interior chamberI2 of the flue. end wall to make these openings 23, the metal is cut onthree sides of the opening and the flap thus formed is bent inwardly toprovide a deij'lector 24 to impart a spiral movement to the air rushingin through the openings, which movement gives the air and burner flame athorough mix resulting in more complete incorporation of the excess airin the heater discharge.

The burner casting I3 comprises a horizontally disposed hollowmixingcylinder 25 and a discharge end offer less resistance to the ilow of airtherethrough, a feature which compensates for the lesser degree ofinjector action at the discharge end. The angular set of the aperturesvalso prevents discharge of the gaseous contents of the flue through thelouvered apertures, which would dissipate the heat laterally of theflue, lnstead of discharging it in a horizontal jet as it iscontemplated by our invention. l

-The flue II is rigidly mounted at itsdischarge end upon a supportingstandard I5 which is movable with respect to the ground I1 upon which itrests. At the burner end, the flue I I is provided with an end wall 22which may be integral with the side walls of the ue II or securedthereto by welding, by bolts, or in any well known Inanner. The end wall22 is secured by screws I3 to a burner casting I9, which is in turn.supported upon a standard 23. This standard 23 is provided at its lowerend with a pedestal 2l which goose neck projection .25 extendingrearwardly from the under side of the cylinder 25. The fuel gas andinjected air enter the cylinder 25 through a rearwardly extendingcylindrical intake hood 21 secured in an opening 28 in the rear wall 23of the cylinder 25 and in axial alignment with the cylinder. The air andgas are thoroughly mixed in the cylinder 25, combustion takes placetherein, and they leave it through a circular opening 33 at its forwardend, entering the flue as an extended llame therein.

The standard 23 consists of a lower solid vertical rod 3|, a T fitting32, threadedly mounted at the upper end of rod 3|, and an upper pipestion 33 having threaded engagement with the T 32 at its lower end andat its upper end with a boss 34 formed on the under side of theprojection 25. This boss 34 has a central vertical bore 35 communicatingwith the interior of the pipe section 33 at the point of threadedengagement. The bore 35 also communicates at its upper end with a bore35 in the gooseneck projection 25, which bore extends horizontally fromthe front end of the projection 25, rearwardly to a vertical leg 31thereof, thence upwardly to a horizontally disposed end portion 33, andthence horizontally to the end of projection 23. The bore 35 at the endportion 38 is threaded and into it is screwed the burner tipor nozzle 33in axial alignment with the intake hood 21.

The forward,v end of the bore 33 has an enlarged portion 43 which isthreaded at its front end to receive the rear end of the cylindricalpreheater 4I, which projects horizontally into the flue chamber I2between the axis and lower wall thereof fora relatively short distance,and is closed at its outer end with a cap 42. A horizontal pipe section43, open at both ends, is'

threadedly mounted at its rear end in thefront end of that portion ofthe bore 35 which is oiv This pipe section projects into 'endsrespectively. The head 43 is provided with a central vertical bore 43,oi' which the lower end is threaded to receive the vertical leg of a T-shaped fitting 53. The horizontal portion of fitting 53 is provided withan axial bore 5I, of

which one end is enlarged and threaded to receive a compression joint 33at the end of a fuel supply pipe 52 which conducts fuel from the sourceof supply to the heater. The other end of the bore 5I is formed with avalve seat 53 and has mounted therein an adjustable needle valve 54 ofstandard construction. Bore 5I communicates with bore 43 through avertical bore 5Ia in the vertical leg of the tting 53. When butanel 6rsimilar liquid fuel is employed, it is conducted as a liquid underpressure to the heater and as it In stamping the passesthrough theneedle valve in fitting 68 its 1 the T 32, and a' horizontal shortnipple 56, which has a threaded connection at one end with the jtting55, and a threaded connection at the other end with a band 46 whichencircles and is rigidly secured to the cylinder 44 about midway of theends of the cylinder. 'I'he interior 61 of the nipple 56 communicates atone end with the lower portion 58a of the interior chamber 58 of thecylinder 44, and at the other end with the interior of the elbow 55,which in turn communicates with the interior chamber of the T 32 and thepipe 33.

Within the cylinder 44 is slidably mounted a piston 59 which is adaptedto impart a reciprocatory motion to a piston rod 60. This rod issuitably secured by a wrist pin connection 60a to the upper face of thepiston and is slidably mounted withinv an axial bore 6| extendingvertically through the cylinder head. 41. As the piston 59 is movedupwardly by the pressure of the fuel entering the cylinder 44 from thepipe 52, it uncovers a main fuel outlet port 62 asits lower end passesabove the level of the bore 51.

At the same time a small fractional part oi the fuel leaks by the pistonbetween it and the walls of the piston 44 into the upper chamber 68h.This leakage then passes through a duet 63 in the cylinder head 41, andthrough a bore 65 of a fitting 66 and issues from the cylinder into apilot tubing v64, which is secured to the cylinder head 41 by means ofthis fitting 66. While not usually necessary, the piston wall may beprovided with a. longitudinal groove 59a to ensure passage of this smallquantity of fuel by the piston to chamber 58h. When the piston reachesthe upper limit of its movement, a valve disk 81, made of syntheticrubber or other suitable material and fastened to the upper face of thepiston, contacts an annular valve seat 68 formed on an annularprojection 68 extending downwardly from the cylinder head 41, andhaltsthe passage of fuel from the cylinder chamber 58 to the pilot tubing 64.

The,pilot tubing 84 terminates at a point such that -when the fuelissuing from it is ignited, the pilot flame will be projected into theneighborhood of the fuel jet issuing from the nozzle 39 of their contactrelationship is of such a character that when the disk is given a rapidmovement of rotation through a small arc, sparks are generated sunicientto ignite the'jet of fuel gas issuing from the adjacent pilot cup 18.This rapid rotational movement is imparted to the disk by'means of amechanism described as follows.

An impulsewheel 88 is loosely mounted upon the pin 14 between thechannel flanges 18 and 15. It is formed with an axial projection 8|extending toward the channel flange 15', having jaws 82 which engage inmating relationship jaws 83 formed on a disk 84 which is keyed orotherwise ixedly secured to the pin 14. The

impulse wheel 88 is resiliently held axially against the`disk 84 bymeans of a spiral spring 85 interposed between the ange 15 and theimpulse wheel. The impulse wheel is provided with an integral dog 86which is resiliently held in a vertically depending position against theupper end of an arm 81 by means of a spring 88 secured at itsl upper endto the dog 88 and at its lower end to the flange 15;y The arm 81 ischannel-shaped in cross section and is arranged withits flanges 88extending toward the upright 12. A block 9| is rigidly secured betweenthe fianges 89 and the arm 81 and is formed with an upwardly extendinglip 92 which mates with a notch 83 formed on the its upper end tol across arm 98 which is integrally formed upon and projects from the arm81 near its lower end, and which extends through, and is free to movevertically in, a slot 91 formed in the standard web 16.

A cylindrical hood 88 formed with a `ring of p .louver openings 99 andsupported loosely upon the elbow 55 serves to enclose all parts of thepilot assembly 45, protecting it from rain when the heater is used inexposed locations, and shielding the pilot flame from wind. An upperhorizontal portion ||l\'| of the hood 98' serves the main burner. Theupper end of the pilot tubing 64 is provided with a mixing cup 18 formedwith a central tapped opening 1| in its bottom wall into which the upperend of the tubing is threaded, and having two air intake openings 1|aalso in its bottom wall which admit air for comv bustion of the pilotflame.

The frame for the igniter mechanism is a channel-shaped upright 12,which is mounted in position by means of a nut 13 threaded upon thenipple 56, by which it is drawn into fixed position against the band 46.A pin 14 is revolvably mounted between iianges 15 and 15' of the up todirect the pilot name toward the fuel jet of the main burner and insuresa quick positive ignition thereof.

The igniter mechanism is so constructed and arranged that .when thepistion 59 is at its lowernlost position, the block 9| and the dog 86are slightly separated, and the upper end of the web 84 rests upon theback of the dog. As the vpiston moves upwardly, the block 9| engages thei dog 86 and rotates the wheel 80 until, as shown in dotted lines inFig. 6, the dog 86 disengages the lip 92 and the impulse wheel 80 isgiven a sudden rotational movement by the action of the spring .88. Thejaws 82 which latch idly Aby jaws 83 during the upward movementof theand designated with the numerals |0| and |02. The

vantage in that when one tank is emptied in the operation of the heatingsystem, it can be shut off from the heaters and refilled while the othertank is furnishing the fuel supply. The fuel outlet pipe |03 is equippedwith shut-off valves |04 and |05 by which the supply network of pipesshown in Fig. 3 can be connected to either or both of the supply tanks.We prefer to divide this supply system of pipes into two or moresub-systems, |01 and |08, each subsystem being provided with a shut-offoperating valve so that either can be operated without the other, orboth can be operated simultaneously, as may be desired.

It will be understood that the heaters may be grouped in one or moresystems for group operation as indicated by the size and otherconditions of the orchard We have illustrated in Fig. 3 a sampleinstallation. In this installation the sub-system of pipes |01 isconnected to heaters disposed about the four edges of a rectangularorchard. The heater units, as will be understood by reference to theabove description of an individual heater unit, are capable of beingplaced with their ilues pointing in any desired direction. Heaters |08are shown in Fig. 3 as directed outwardly toward the boundaries of theorchard, and, in an installation such as shown in Fig. 3, can be firedin advance of the firing of the remaining heaters H0 supplied by pipesystem |08, which heaters are located in the central portions of the or#chard. Heaters ||0 are shown with their nues pointing toward theprevailing movement of cold air asindicated by the arrows A.

The liquid fuel, indicated in Fig. 2 by the numeral ||2, is held underpressure in the tanks. As the tank is gradually emptied of its supplythe pressure therein tends to drop. Since the pressure of fuel at theheaters determines the rate of flow of fuel thereto, and consequentlythe rate of liberation of thermal units, it is desirable to maintain afairly constant pressure in the supply tanks. VWe accomplish this byproviding a tank heater H3, which heater may be similar to those used inthe orchard. Such a heater may be fed from`the fuel outlet pipe |03through a pipe II4, and the feed controlled by a. needle valve such asshown at 54. in Fig. 6. Water in a closed system, which is provided withan expansion tank '||9, is warmed in a coil ||5 and conducted through apipe ||6 to a heating loop ||1 mounted within the fuel tank and adjacentits bottom, and thence back to the heater ||3. By regulation of the flowof fuel to heater ||3, and by regulation of the flow of water by meansof a valve H8, the liquid fuel within either tank can be raised to anydesired temperature, and the pressure thereby increased to any desireddegree, maintaining a. constant pressure at the heaters or varying it asdesired, according to the varying heating needs of the orchard. It willalso be apparent .that by selective regulation of the needle valves 54,the quantity of fuel consumed in any individual heater unit and theresultant liberated thermal units can be varied at will. By means yofthe valves 54 those heaters at 'greatest dis for example a pressure ofseventy pounds at 'le Il.

Ato hydraulic frictionv of the fuel liquid within the distributing pipesystem. When the liquid fuel under pressure reaches vone of the needlevalves 54 and passes therethrough, its pressure is reduced. Inaccordance with the physical properties of this type of liquid fuel, itis gasified as it leaves the needle valve, and as a gas enters thecylinder chamber 5B. Here it exerts pressure upon the piston 59 whichbegins to move upwardly. Gas leaks by the piston or passes through thegroove 59a into the upper cylinder chamber 58h and thence by the pilottubing 64 to the pilot cup 10, where it is mixed with air and is jettedupwardly. As the piston 59 moves upward, it operates the arm 89 which,by the train of devices heretofore described, generates igniting sparksadjacent the pilot jet of gas. In the meantime the piston 59 hasuncovered the port 62,.and fuel gas passes from the chamber 58 throughthe bore 51, elbow 55, fitting 32, pipe section 33, bore 35, bore 40,preheater 4|, pipe section 43, bore 38, to the nozzle 39, from which itissues in a jet of high velocity. This fuel jet is ignited by the pilotflame issuing up- Wardly from the pilot tubing 64 and then enters theintake hood 21.

As it streams rapidly into the hood 21 and mixing cylinder I9, air isdrawn in through the annular gap between the nozzle 39 and hood 21, andis carried along with the fuel jet into the mixing chamber within themixing cylinder I9. This air is sufficient for complete combustion. Nosoot, smoke, or other unburned products are blown from the heater, butwe provide the flue with louvers I5 to supply a substantial excess ofair as has been heretofore described. The prinl cipal purpose, fulfllledby these louvers and the openings 23 in the end Wall 22 of the flue, is

that of mixing a substantial excess of air with P: 1/2V2D wherein Vequals the velocity, D the density of the fluid and P the amount ofreduced pressure, so that, 1/2 the velocity squared times the densitygives P, the amount of reduced pressure.

As the liquid fuel expands and vaporizes upon entering the cylinderchamber 58, heat of vaporization is supplied from surrounding bodies andatmosphere, greatly reducing their temperature and that of the gasitself. This refrigerating effect is partly overcome after the heater isin normal operation by the radiation and conduction-of heat from theburner flame. To assist in offsetting this refrigerating effect, and toensure complete gasification of any liquid droplets,'we provide thepre-heater 4| which is interposed in the path of the fuel to the nozzleeffect is produced inside saidmtubular member n which has the propertyof increasing the axial 'velocity flow of heated air from the open endof It will be observed that the heaters Acreate a focused movement ofhot air in any desired horizontal direction. These horizontal streamsof\hot ir mingle with and raise the temperature ofatd'ie lowermoststratum of air in the orchard, which, because of" its resultant decreaseindcnsity, begins a gentle upward movement. Gradually the entire layerof air below the ceiling of the upper layer of warmer air, which isabove the danger point, is itselil brought up to a safe temperature. Notuntil all areas of this cold lower layer are warmed to the ceilingtempera-ture can any of the air streaming from the heaters pierce theceiling with resultant loss of unused thermal units.. Were the heatersto discharge their hot gases vertically upward, instead of horizontallyas practiced by our invention, the lower stratum below the ceiling wouldhave spotted areas of .hot air over theheaters, and relatively coolerareas therebetween, with the result that the air in the heated areaswould penetrate the ceiling and be ineffective in Warming the air aroundthe trees, and this penetration of the ceiling would occur before theentire ground layer was brought up to the safety temperature. Weconsequently conserve all the heat units potentially present in thefuel, first by completely burning it, and then by mixing it with coolair in the iiue and discharging it horizontally at a high velocity infocused fashion in large streams of relatively low temperature.

While We have described one method of igniting the burner in our heater,we do not limit ourselves to this one method of practicing ourinvention. Lighting of the burner may be` effected by a remotelycontrolled electric spark, or by making provision for the generation offlame temperatures adjacent the burner jet by chemical means such as theadsorption of the .fuel gas by metals or other materials when the fuelgas reaches the heater.

We desire not to limit the scope of our inven-'` tion to any particularform or embodiment thereof which may have been described above, but havedefined it in the following claims.

We claim as our invention: p l. An orchard heater for heating and movinglarge volumes of heated air horizontally along the ground to interminglewith the cool atmosphere around the trees and warm the same, comprisingan elongated circular tubular member substantially completely closed atone end and open at the other, openingsin the wall of said tubular4member in somewhat spaced relation and extending from one end to theother thereof, means for storing a supply of fuel under pressure andconveying said fuel to orchard heaters distributed about .an orchard,means in said tubular member for burning said fuel movement of theproducts of combustion thereof.

drawing atmospheric air inside said tubular member to support combustionand excess air to cool the heat of combustion and to cool the Wall ofsaid tubular member so that an injector said tubular member, said largevolume of heated air spreading out near the ground and warming theatmospheric air around and in the trees of the orchard.`

2. An orchard heater for heating and moving large volumes of heated airhorizontally along the ground around and adjacent the trees tointermingle with the cool ground air and warm the same comprising around straight elongated tubular member located in a horizontal positionnear the ground with one end substantially completely closed and theother end open, louvres in the wall of said tubular member in somewhatspaced relation and extending from one end to the other of said tubularmember, a source of fuel supply and means for leading fuel to saidtubular member, burner means at the closed end of said tubular member toconsume said fuel the burning thereof drawing atmospheric air much inexcess of that needed to support combustion through the said louvres inthe wall of said tubular member said air tending to support combustionand .the excess thereof tending to cool said products of combustion andthe Wall of said tubular member which produces an injector effect insideofsaid tubular member which increases `-the 'velocity flow of heated airpassing through and out of said tubular member which large volume ofheated air intermingles with the cold air around the ground and thelower parts of the trees and quickly raises the temperature thereof toa` safety point.' f

3.1An orchard heater for heating and moving large volumes of heated airhorizontally along the ground and adjacent the trees tointermingle withthe cool ground air and warmzthesame, comprising an elongated tubularmember located in a horizontal position nearthe'ground one end of whichis `substantially completelyV l'closed and the other open, louvres inther Wallvof said tubular member, a source of fuelsupply and means forconveying it to `said tubular member, a means at the closed end of saidtubular member for consuming said fuel, the sizeof said tubular memberrelative to the size of the flame produced in said tubular member beingsuch that air much in excess of that needed for combustion is drawninside said tubular member by the burning of said fuel which air acts tosupeffect is produced inside said tubular member which has the' eiect ofgreatly increasing the velocity flow of 'heated air from the open end ofsaid tubular member, no flame of combustion appearing at the open end ofsaid tubular member or popping out of said louvres.

vWALTER A. LEA. EARL VINCENT EHRHARDI'.

